A method is disclosed for the automated synthesis of phase shifters. Phase
shifters comprise circuits used to remove effects of structural
dependencies featured by pseudo-random test pattern generators driving
parallel scan chains. Using a concept of duality, the method relates the
logical states of linear feedback shift registers (LFSRs) and circuits
spacing their inputs to each of the output channels. The method generates
a phase shifter network balancing the loads of successive stages of LFSRs
and satisfying criteria of reduced linear dependency, channel separation
and circuit complexity.